This invention relates to image forming apparatus which uses an image forming sheet of such a characteristic that it is rendered photosensitive by preheating prior to exposure, forms a latent image by exposure to a light image and then produces a visible image by heat development.
There has heretofore been known an image forming sheet which is rendered photosensitive by heat activation and which can form thereon a visible image in the photosensitive area by exposure to a light image and then by heat development. This image forming sheet requires neither the wet process for development nor the provision of a dark room for loading on and unloading from image forming apparatus, and can be handled in a light room.
According to the arrangement of such image forming apparatus, it is also possible that after information is once selectively recorded in a desired frame of the image forming sheet, the image forming sheet can be loaded again on the image forming apparatus for additionally recording information in other frames of the sheet.
This invention has for its object to provide image forming apparatus which permits handling of the image forming sheet in a light room, and hence is simple-structured, and permits recording and development of information on the image forming sheet by the dry process.
In the case of providing a plurality of image forming area on one image forming sheet so that information can be additionally recorded as in the abovesaid case, it is desirable that preheating and heat development of a desired one of the image forming areas do not exert any influence on the other areas. This is especially important when the image forming areas are provided in close proximity. Further, it is desired, of course, that the image forming apparatus has high resolution as is the case with ordinary other image recording apparatus. High resolution is required especially when an image of a subject is recorded, on a reduced scale, in each one of a number of image forming areas as in the case of a microfilm or microfiche. Incidentally, the image forming sheet must be heated for making it photosensitive and development; accordingly, there is a fear that the image forming sheet is deformed by heat to make it impossible to perform recording with high resolution. Moreover, since one recording operation involves at least three processes of preheating, exposure and heat development, the recording speed of the image forming apparatus using this image forming sheet is likely to be low; this is undesirable for successive recording of many subjects.
Another object of this invention is to provide image forming apparatus which enables high-resolution recording untouched by heating processes.
Another object of this invention is to provide image forming apparatus which permits high-speed recording.
Another object of this invention is to provide image forming apparatus which ensures to prevent a heating process of one image forming area from affecting the other image forming areas and hence permits providing the image forming areas in close proximity.
Still another object of this invention is to provide image forming apparatus which ensures to prevent the image forming sheet from being thermally distorted by a heating process of a desired one of a plurality of image forming areas.